This year's Arles festival, one of the most valuable and venerable stops on the international photography circuit, is as stimulating as ever.

The 47th edition of Les Rencontres de la Photographie opened July 4 and remains on view through September 25. Overseen by Sam Stourdze, former director of the Musee de l'Elysee in Lausanne, Switzerland, the Arles festival is an exuberant, sprawling affair, with exhibits and activities located throughout this beautiful old Roman town. With exhibition maps firmly in hand, visitors set off through a maze of narrow walkways on a kind of self-guided Easter Egg hunt. It is satisfying to find each of the designated exhibition addresses and, in the process, to come to know the town itself.

There are 40 shows in this year's festival, reflecting the combined effort of more than 30 curators, with an accompanying program of lectures and round-table discussions. Photo-books are taken very seriously here—the festival includes a vast roundup of recent publications, as well as tabletop displays of new titles by about 80 small and medium-size publishing houses. All this adds up to a fascinating visual and conceptual overload. It is clearly possible to see "everything" here, but that takes a special kind of diligence and endurance.

The strength of the Arles festival is a product of its scale and diversity. At the same time, however, a handful of organizing themes help bring the overall experience into conceptual focus. The larger themes this year include "Street," a fresh look at the classic idea of street photography. A show I helped organize with Howard Greenberg and Bob Shamis—"Sid Grossman: From Document to Revelation, His Photographs and Legacy"—provided an historical foundation for the larger concept here. As Grossman's first career survey in at least 30 years, and the first ever in Europe, this selection of vintage prints highlighted a profoundly original and influential body of work.

The "Street" theme was extended in fresh directions by a solo show by the Irish photographer Eamonn Doyle; a two-person presentation of the work of Garry Winogrand and young talent Ethan Levitas; conceptual work from the 1970s by British photographer Peter Mitchell; and mesmerizing video pieces by Christian Marclay.

Courtesy of Les Rencontres de la Photographie.

Other festival themes included "After War," with strong solo exhibitions by noted French and British photojournalists: Yan Morvan's large-format color images of historical battlefields, and a survey of the non-combat work of Don McCullin. A wide-ranging group show, "Nothing by Blue Skies: Looking Back at the Media's Image of September 11," explored the power, ubiquity, and malleability of news images that, 15 years later, remain potent and raw.

Other interesting shows were grouped under such organizational themes as "Africa Pop" (the music and film cultures of Mali and Nigeria); "Monsters & Co." (film stills of classic Hollywood monsters; the world of UFO abductions); and "Singular!—Quirky Collections" (historical collections of photographs of transvestites, the Statue of Liberty, and work done for the French satirical magazine Hara Kiri).

"I Am Writing to You From a Far-Off Country," joined two exhibitions by globe-trotting image-makers: Yann Gross's photographs in the Amazon, and collaborative work done in Kosovo, Afghanistan and Washington, DC, by photographer Seamus Murphy and singer and writer P. J. Harvey.

Another intriguing exhibition, "Fabulous Failures—The Art of Embracing Serendipity and Mistakes," presented contemporary work by artists such as Kent Rogowski, Lucas Blalock and Joachim Schmid.

The Arles festival can be relied on to provide a fresh, smart, and often surprising look at the current state of the medium. The shows are not all of equal merit, of course, and the sheer scale and variety of the gathering can be daunting. Nonetheless, Arles exudes an energizing spirit of discovery and risk-taking. In part, it serves an important need simply by being geared to viewers rather than buyers—except for the book publishers' tables, there are no price stickers on view. As a result, Arles stands distinctly apart from that other, all-too-familiar, model of the sprawling group exhibition: the commercial art fair.

With all its energy, insights, and occasional dead ends, Arles provides an annual snapshot of the place of the lens-based image in contemporary life. This long ago ceased to be any simple matter of a photographic "art" standing aloof from the vital messiness and cross currents of modern society. We know that photography is an art, in part, because it is woven into the heart of this cultural condition. At once subject and object, mirror and window, photography demands to be understood precisely because it cannot be escaped.